C
ColdFeet
Hi all,
I'm new to these forums. I'm not a plumber though I have a technical background, and I've been trying to work out the CH system in a house that I've just moved into.
Basically, the heating system consists of a condensing boiler and an Albion Mainsflow indirect combination thermal store with, I believe, two coils: an upper one for hot water and a lower one for the underfloor heating. The underfloor heating is connected directly to the lower coil via a pump and a crude manifold with valves to the UFH heating pipes - I can see no evidence of a mixing valve.
What perplexes me is the control. There is only one thermostat on the store, positioned at the bottom. When the central heating is turned on via the timeswitch, this thermostat is pulled down rapidly and within a minute or two brings the boiler on. (I would expect this as obviously the UFH return would be quite cold initially.) I have read that underfloor heating flow temperature needs to be significantly lower than a radiator setup, but with the thermostat at the bottom of the tank I don't see how we can be sure what the temperature at the top of the CH coil might be, even if the thermostat is initially set low at, say, 50 degrees C, and I'm concerned that it could get too hot.
Do you think that this is a reasonable concern?
Of course I could simply lower the temperature of the boiler outlet temperature to ensure that the store can never get too hot, but that might compromise the HW production in winter when the incoming water is cold. On the plus side, it might ensure that the boiler is condensing more of the time. It would also limit heat input into the store, meaning that it might be unable to cope with combined heating and hot water production. It's also scarcely a fail-safe solution.
Thanks.
I'm new to these forums. I'm not a plumber though I have a technical background, and I've been trying to work out the CH system in a house that I've just moved into.
Basically, the heating system consists of a condensing boiler and an Albion Mainsflow indirect combination thermal store with, I believe, two coils: an upper one for hot water and a lower one for the underfloor heating. The underfloor heating is connected directly to the lower coil via a pump and a crude manifold with valves to the UFH heating pipes - I can see no evidence of a mixing valve.
What perplexes me is the control. There is only one thermostat on the store, positioned at the bottom. When the central heating is turned on via the timeswitch, this thermostat is pulled down rapidly and within a minute or two brings the boiler on. (I would expect this as obviously the UFH return would be quite cold initially.) I have read that underfloor heating flow temperature needs to be significantly lower than a radiator setup, but with the thermostat at the bottom of the tank I don't see how we can be sure what the temperature at the top of the CH coil might be, even if the thermostat is initially set low at, say, 50 degrees C, and I'm concerned that it could get too hot.
Do you think that this is a reasonable concern?
Of course I could simply lower the temperature of the boiler outlet temperature to ensure that the store can never get too hot, but that might compromise the HW production in winter when the incoming water is cold. On the plus side, it might ensure that the boiler is condensing more of the time. It would also limit heat input into the store, meaning that it might be unable to cope with combined heating and hot water production. It's also scarcely a fail-safe solution.
Thanks.
